feat: add TypeScript lessons and learning panel

- Introduced a new script to check TypeScript lesson files for errors.
- Created a main TypeScript file to render lessons and their details.
- Added lesson definitions with starter and answer codes.
- Implemented a user interface for navigating and running lessons.
- Styled the application with CSS for a better user experience.
- Updated README to reflect the new TypeScript section and usage instructions.

04-dom-events-async/05-form-submit-and-prevent-default/README.md

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+# 练习 5：表单提交和 preventDefault
+
+## 目标
+
+学会拦截表单默认提交，并把输入内容渲染到页面。
+
+## 你要练什么
+
+- `submit` 事件
+- `preventDefault()`
+- 表单值读取
+- 动态追加列表项
+
+## 任务
+
+- 提交表单时阻止页面刷新
+- 读取输入框内容
+- 把内容加入到待办列表
+- 提交后清空输入框
+
+## 文件
+
+- [starter.html](/Users/lijiaqing/home/wwwroot/front-end-example/04-dom-events-async/05-form-submit-and-prevent-default/starter.html)
+- [starter.js](/Users/lijiaqing/home/wwwroot/front-end-example/04-dom-events-async/05-form-submit-and-prevent-default/starter.js)
+- [answer.html](/Users/lijiaqing/home/wwwroot/front-end-example/04-dom-events-async/05-form-submit-and-prevent-default/answer.html)
+- [answer.js](/Users/lijiaqing/home/wwwroot/front-end-example/04-dom-events-async/05-form-submit-and-prevent-default/answer.js)